- Heck Reaction over Pd-Loaded ETS-10 Molecular Sieve
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ETS-10 molecular sieve has been used as a catalyst in the shape-selective photo catalytic decomposition of aromatic molecules, Aldol-type condensations, aniline oxidation, acylation reactions, and alcohol dehydrogenation. The carbon-carbon coupling of different aryl halides with ethyl acrylate over Pd-loaded ETS-10 was presented. The influences of the Pd content, nature of the base and reactivity of the different substrates and reactants on the coupling reaction were presented. The catalyst exhibited high activity and selectivity towards the carbon-carbon coupling of aryl halides with olefins, even at low concentrations of palladium (0.009 to 1.4 mole % with respect to the substrate). In the case of the coupling of ethyl acrylate with iodobenzene, 96% conversion of iodobenzene with > 98% selectivity could be obtained within 1 hr over a 0.2 wt % Pd-loaded catalyst. The catalyst activated aryl bromide and chloride substrates, and was heterogeneous. Aryl bromide, chloride and their derivatives exhibited moderate activity with ethyl acrylates. Organic bases led to higher catalytic activity than inorganic bases. The catalysts could be reused and reactivated by washing with a moderate decrease in activity. The substrate reactivity increased with electron-withdrawing substituents.
- Waghmode, Suresh Babasaheb,Wagholikar, Smita Girish,Sivasanker, Subramanian
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Read Online
- Synthesis, characterization, photophysical properties, and catalytic activity of an SCS bis(N-heterocyclic thione) (SCS-NHT) Pd pincer complex
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Treatment of 1,3-bis(3′-butylimidazolyl-1′-yl)benzene diiodide with elemental sulfur in the presence of a base produced a bis(N-heterocyclic thione) (NHT) pincer ligand precursor. Its reaction with PdCl2(CH3CN)2 produced chloro[1,3-bis(3′-butylimidazole-2′-thione-κ-S)benzene-κ-C]palladium(ii), a 6,6-fused ring SCS-NHT palladium pincer complex. This air stable compound is, to our knowledge, the first SCS pincer complex that utilizes N-heterocyclic thione (NHT) donor groups. The molecular structures of the ligand precursor and the palladium complex were determined by X-ray crystallography and computational studies provided insight into the interconversion between its rac and meso conformations. The photophysical properties of the complex were established, and its catalytic activity in Suzuki, Heck, and Sonogashira cross-coupling reactions was evaluated.
- Tyson, Ginger E.,Tokmic, Kenan,Oian, Casey S.,Rabinovich, Daniel,Valle, Henry U.,Hollis, T. Keith,Kelly, John T.,Cuellar, Kristina A.,McNamara, Louis E.,Hammer, Nathan I.,Webster, Charles Edwin,Oliver, Allen G.,Zhang, Min
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Read Online
- Discovery of a novel inhibitor of nitric oxide production with potential therapeutic effect on acute inflammation
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Inflammation as a host's excessive immune response to stimulation, is involved in the development of numerous diseases. To discover novel anti-inflammatory agents and based on our previous synthetic work on marine natural product Chrysamide B, it and a series of derivatives were synthesized and evaluated for their anti-inflammatory activity on inhibition of LPS-induced NO production. Then the preliminary structure–activity relationships were conducted. Among them, Chrysamide B is the most potent anti-inflammatory agent with low cytotoxicity and strong inhibition on the production of NO (IC50 = 0.010 μM) and the activity of iNOS (IC50 = 0.082 μM) in LPS-stimulated RAW 264.7 cells. Primary studies suggested that the mechanism of action may be that it interfered the formation of active dimeric iNOS but not affected transcription and translation. Furthermore, its good performance of anti-inflammatory effect on LPS-induced multiple inflammatory cytokines production, carrageenan-induced paw edema, and endotoxin-induced septic mice, was observed. We believe that these findings would provide an idea for the further modification and research of these analogs in the future.
- Zhu, Long-Qing,Fan, Xiao-Hong,Li, Jun-Fang,Chen, Jin-Hong,Liang, Yan,Hu, Xiao-Ling,Ma, Shu-Meng,Hao, Xiang-Yong,Shi, Tao,Wang, Zhen
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supporting information
(2021/05/26)
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- Oxiranyl remote anions from epoxy cinnamates and their application towards the synthesis of α,β-epoxy-γ-butyrolactones
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A series of α,β-epoxy-γ-butyrolactones were synthesized in moderate yields via oxiranyl remote anions derived from epoxy cinnamate esters. The key synthetic step involved deprotonation of the β-position of α,β-epoxy cinnamate derivatives where the generated β-anion was stabilized by remote chelation from an ester group. The substitution reaction of the anion with a variety of ketones, followed by cyclization, readily furnished the desired substituted α,β-epoxy-γ-butyrolactones.
- Sermmai, Patpanat,Ruangsupapichat, Nopporn,Thongpanchang, Tienthong
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supporting information
(2020/11/19)
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- Copper-Photocatalyzed Contra-Thermodynamic Isomerization of Polarized Alkenes
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The contra-thermodynamic isomerization of α- and β-substituted cinnamate derivatives catalyzed by the Cu(OAc)2/rac-BINAP complex under blue light irradiation is reported. The use of an oxazolidinone template, which favored the complexation of the copper catalyst to the substrate, allowed the E → Z isomerization of the catalytically formed chromophore under simple and robust reaction conditions in good to excellent ratios. The mechanism of this process based on the transient formation of a chromophore was also studied.
- Bouillon, Jean-Philippe,Brégent, Thibaud,Poisson, Thomas
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supporting information
p. 7688 - 7693
(2020/10/09)
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- Synthesis and discovery of 18β-glycyrrhetinic acid derivatives inhibiting cancer stem cell properties in ovarian cancer cells
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Despite advances in ovarian cancer treatment, the five-year overall survival rate is less than 30% with the presence of cancer stem cells (CSCs). To develop CSC-targeting therapy, a series of 18β-glycyrrhetinic acid (GA) derivatives containing cinnamamide moiety have been designed, synthesized, and screened for their antiproliferative activity in SKOV3 and OVCAR3 cells. Most of the compounds exhibited stronger antiproliferative activity than GA, and compound 7c was the most active one. Further biological studies showed that compound 7c could induce apoptosis and suppress migration. In addition, compound 7c could not only observably decrease the colony formation and sphere formation ability, but also significantly reduce the CD44+, CD133+, and ALDH+ subpopulation in SKOV3 and OVCAR3 cells. In conclusion, these results indicate that compound 7c is a promising anti-CSC agent for further anti-ovarian cancer studies.
- Li, Xiaojing,Liu, Yihua,Wang, Na,Liu, Yuyu,Wang, Shuai,Wang, Hongmin,Li, Aihua,Ren, Shaoda
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p. 27294 - 27304
(2019/09/12)
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- Recyclable Pd ionic catalyst coated on cordierite monolith for high TOF Heck coupling reaction
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Abstract : Pd 2 + ionic catalyst, Ti 0.97Pd 0.03O 1.97 was coated over cordierite monolith by solution combustion method. The catalyst coated on the cordierite is nano-crystalline as seen from XRD studies. Coated catalyst was used for Heck coupling reactions with different substrates of aryl halides and olefins. Thus handling nano-crystalline catalyst powder is avoided by fixing it on a solid catalyst cartridge. Heck coupled products were characterized using 1H NMR, 13C NMR, Mass and FTIR spectroscopy. This catalyst showed high selectivity towards Heck coupling reaction. Turnover frequencies (TOF) for each of the reactions were found to be very high. The catalyst was recycled up to 7 times with total TOF 3017 h - 1, which is found to be a new green technique in the Heck coupling reaction. Graphical abstract: Ti 0.97Pd 0.03O 1.97 catalyst is coated on cordierite monolith honeycomb (HC) by solution combustion method and it is used in the Heck coupling reaction. Reactions are done in a specially designed flask. Catalyst is recycled for 7 times. The total turnover frequency (TOF) after 7 cycles was 3017 h - 1. [Figure not available: see fulltext.].
- Bhat, Shrikanth K,Prasad, Jagadeesh D,Hegde
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- Synthesis and structural characterization for novel mixed-donor ligand palladium (II) based on graphene and oxime: its application as a highly stable and efficient recyclable catalyst
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In this article, the palladium (II) mixed-ligand complex synthesized with reduced graphene oxides containing tetraethoxysilane and menthone oxime was used as an efficient solid catalyst for the Heck coupling reaction. To maintain stability and catalytic activity in the C–C bond reaction, graphene was considered due to the available surface as the solid support. Then, the structure of new heterogeneous catalyst was investigated by FT-IR, UV–Vis DRS, FE-SEM, EDX, AFM, XRD, ICP-OES, Raman, and TGA. The newly synthesized nanocatalyst have beneficial properties, including product’s easy separation, the shorter time to react, purity products (yield 79–99%), and easier work-up procedure. Furthermore, the catalyst was reused six times without significant degradation in catalytic activity and performance.
- Ashiri, Samira,Mehdipour, Ebrahim
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p. 2383 - 2393
(2018/08/28)
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- Preparation of a novel palladium catalytic hydrogel based on graphene oxide/chitosan NPs and cellulose nanowhiskers
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The present paper focuses on the synthesis of a novel hydrogel support by combining polysaccharides (chitosan NPs and dialdehyde cellulose nanowhiskers) and graphene oxide nanosheets to obtain a biocompatible material for catalytic applications. The hydrogel was synthesized via green chemistry processes and used as a support to prepare Pd nanoparticles. Finally, the hydrogel@Pd NPs was employed as the catalyst in the Mizoroki-Heck reaction to generate new C-C bonds. SEM analysis indicated that the hydrogel has macroporous morphology, which is in good correlation with its high crosslinking degree. The as-synthesized nanocomposite hydrogel exhibits beneficial properties such as ease of separation and excellent recyclability for at least six cycles without considerable loss in its activity. The yields of the products range from 81% to 98%. Additionally, this study provides the possibility to perform the Mizoroki-Heck reaction with aryl chloride in the presence of the as-prepared catalyst.
- Ashiri, Samira,Mehdipour, Ebrahim
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supporting information
p. 32877 - 32885
(2018/10/15)
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- Control of Chemo-, Regio-, and Enantioselectivity in Copper Hydride Reductions of Morita-Baylis-Hillman Adducts
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Nonracemically ligated copper hydride can be used to effect tandem SN2′/1,2-reductions of racemic Morita-Baylis-Hillman (MBH) acetates to access enantioenriched chiral allylic alcohols with defined olefin geometry. MBH esters, including those w
- Linstadt, Roscoe T. H.,Peterson, Carl. A.,Jette, Carina I.,Boskovic, Zarko V.,Lipshutz, Bruce H.
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supporting information
p. 328 - 331
(2017/04/21)
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- The effect of framework functionality on the catalytic activation of supported Pd nanoparticles in the Mizoroki–Heck coupling reaction
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Palladium nanoparticles (Pd-NPs) were supported on functional and nonfunctional Co-coordination polymers (Pd/CoBDCNH2 and Pd/CoBDC). Advanced analytical techniques revealed that Pd-NPs are supported on the external surface of the polymer framework and the functionalized framework possesses effective influence to prevent Pd-NP aggregation. Supported Pd-NPs were effectively applied as heterogeneous recyclable catalysts in the Mizoroki–Heck C–C cross coupling reactions of iodobenzene and either aromatic or aliphatic terminal alkenes. Catalytic results exhibited that highly dispersed Pd-NPs with low loading (1%) on the functional polymer (Pd/CoBDCNH2) are more effective than aggregated Pd-NPs with high loading (9%) on the nonfunctional polymer (Pd/CoBDC). Both catalysts can simultaneously provide high activity and selectivity to E-coupled products, high efficiency in low amounts, easy separation of heterogeneous catalyst and appropriate performance in the recycling reaction without addition of a reducing agent.
- Ashouri, Fatemeh,Zare, Maryam,Bagherzadeh, Mojtaba
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p. 107 - 115
(2017/01/22)
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- An ionic liquid catalyzed probase method for one-pot synthesis of α,β-unsaturated esters from esters and aldehydes under mild conditions
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A one-pot synthesis of α,β-unsaturated esters from unactivated esters and aldehydes using strong bases, such as sodium alkoxide and potassium tert-butoxide, was reported. However, the ionic liquid (IL) catalyzed probase method for producing α,β-unsaturated esters was not reported until now. In this work, a series of ILs with fluoride anions were firstly prepared and used as catalysts in combination with the probase N,O-bis(trimethylsilyl) acetamide (BSA) for the α,β-unsaturated esters synthesis. This process could also be promoted through the introduction of another IL with Lewis acid sites. The yield and selectivity of the product could reach up to 84.2% and 95.0%, respectively, when [Bmim]F was used in combination with [Bmim]Cl/AlCl3 (the molar fraction of AlCl3 is 0.67). The mechanism investigation through GC-MS indicates that BSA would convert into onium amide, which acted as a strong base for α-H abstraction, with the catalysis of [Bmim]F. Meanwhile, [Bmim]Cl/AlCl3 played an important role in the condensation step between enolates and aldehydes. On the basis of mechanism insights, kinetic and thermodynamic studies were also carried out for a better understanding of this new route.
- Wang, Gang,Xu, Yiming,Zhang, Suojiang,Li, Zengxi,Li, Chunshan
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p. 4838 - 4848
(2017/10/23)
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- Tetrakis [N-(2-pyridyl) sulfonamide] di palladium: synthesize, X-ray diffraction, antibacterial properties and as a novel binuclear Pd-complex for coupling reactions
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The N-(2-pyridyl) 4-toluene sulfonamide as a free ligand (PTS) was prepared from the reaction of 2-amino pyridine and 4-toluenesulfonyl chloride in the presence of potassium hydroxide solution 1?M as a base and THF was used as a solvent. The complex tetrakis [N-(2-pyridyl) sulfonamide] di palladium (1) (Pd2L4) was also prepared from the reaction of PdCl2(CH3CN)2 using (PTS) in the presence of NaOH 0.5?M and its application in Heck and Suzuki reactions. This complex consists of a binuclear unit consisting of four ligands linked to two palladium atoms via the nitrogen of pyridines ring and the nitrogen of sulfonamides. These compounds were confirmed by FT-IR and 1H NMR spectroscopy. Moreover, the structure of the complex was studied by single-crystal X-ray diffraction method. The green crystal of Pd2L4 [L?=?N-(2-pyridyl) sulfonamide](1) was found to crystallize in the monoclinic space group C2/c with a?=?18.2013(19), b?=?19.7544(16), c?=?17.2898(19) ?, β?=?120.179(8) °; V?=?5374.0(9) ?3; Z =?4; the final R1?=?0.0894, wR2?=?0.1754 (or 5867 observed reflections and 318 variables). The Pd–Pd distance is 2.567(2) ?. In addition, PTS and Pd2L4 presented different antibacterial behaviors. The free ligand was active against Staphylococcus aureus and Escherichia coli, but the complex was inactive against them.
- Mehdipour, Ebrahim,Shafieyoon, Parvaneh,Salahvarzi, Maryam,Amani, Vahid
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p. 1575 - 1582
(2017/06/06)
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- A New Mode of Operation of Pd-NHC Systems Studied in a Catalytic Mizoroki-Heck Reaction
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Metal complexes bearing N-heterocyclic carbene (NHC) ligands are typically considered the system of choice for homogeneous catalysis with well-defined molecular active species due to their stable metal-ligand framework. A detailed study involving 19 different Pd-NHC complexes with imidazolium, benzimidazolium, and triazolium ligands has been carried out in the present work and revealed a new mode of operation of metal-NHC systems. The catalytic activity of the studied Pd-NHC systems is predominantly determined by the cleavage of the metal-NHC bond, while the catalyst performance is strongly affected by the stabilization of in situ formed metal clusters. In the present study, the formation of Pd nanoparticles was observed from a broad range of metal complexes with NHC ligands under standard Mizoroki-Heck reaction conditions. A mechanistic analysis revealed two different pathways to connect Pd-NHC complexes to "cocktail"-type catalysis: (i) reductive elimination from a Pd(II) intermediate and the release of NHC-containing byproducts and (ii) dissociation of NHC ligands from Pd intermediates. Metal-NHC systems are ubiquitously applied in modern organic synthesis and catalysis, while the new mode of operation revealed in the present study guides catalyst design and opens a variety of novel opportunities. As shown by experimental studies and theoretical calculations, metal clusters and nanoparticles can be readily formed from M-NHC complexes after formation of new M-C or M-H bonds followed by C-NHC or H-NHC coupling. Thus, a combination of a classical molecular mode of operation and a novel cocktail-type mode of operation, described in the present study, may be anticipated as an intrinsic feature of M-NHC catalytic systems.
- Astakhov, Alexander V.,Khazipov, Oleg V.,Chernenko, Andrey Yu.,Pasyukov, Dmitry V.,Kashin, Alexey S.,Gordeev, Evgeniy G.,Khrustalev, Victor N.,Chernyshev, Victor M.,Ananikov, Valentine P.
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supporting information
p. 1981 - 1992
(2017/06/14)
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- Suzuki and Heck cross-coupling reactions using ferromagnetic nanoparticle-supported palladium complex as an efficient and recyclable heterogeneous nanocatalyst in sodium dodecylsulfate micelles
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A novel heterogeneous Pd catalyst was synthesized by anchoring Pd(II) onto 4′-(4-hydroxyphenyl)-2,2′:6′,2″-terpyridine-coated Fe3O4 (FMNPs@TPy-Pd). This catalyst has been demonstrated for the first time as a recoverable and reusable heterogeneous nanocatalyst in Suzuki and Heck cross-coupling reactions. The catalyst is very easy to handle and is environmentally safe and economical. FMNPs@TPy-Pd was characterized using transmission and scanning electron microscopies, X-ray diffraction, and Fourier transform infrared and energy-dispersive X-ray spectroscopies.
- Bahrami, Kiumars,Khodaei, Mohammad M.,Meibodi, Farhat Sadat
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- Magnetic iron oxide nanoparticles–N-heterocyclic carbene–palladium(II): a new, efficient and robust recyclable catalyst for Mizoroki–Heck and Suzuki–Miyaura coupling reactions
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A new and efficient nanoparticle–N-heterocyclic carbene–palladium complex was synthesized and characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, field emission scanning electron microscopy, energy-dispersive X-ray analysis, X-ray diffraction, transmission electron microscopy, elemental analysis, inductively coupled plasma analysis and vibrating sample magnetometry. This catalytic system was found to be a highly active catalyst in the Mizoroki–Heck and Suzuki–Miyaura cross-coupling reactions. These reactions were best performed in dimethylformamide and water, respectively, in the presence of only 0.054 mol% of palladium under mild conditions. Moreover, the catalyst could be recovered easily and reused at least ten times without any considerable loss of its catalytic activity. Copyright
- Hajipour, Abdol R.,Tadayoni, Nayereh S.,Khorsandi, Zahra
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p. 590 - 595
(2016/07/16)
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- Synthesis and characterization of bifunctional lipophilic and basic mesoporous organosilica supported palladium nanoparticles as an efficient and ecofriendly nanocomposite in aqueous Heck reaction
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In the present study, a highly ordered mesoporous organosilica nanocomposite having modified pore channels with both lipophilic and basic units, SBA-R/Im-NH2, was synthesized through surfactant-templated sol-gel methodology and post modification process. The nanocomposite with ionic liquid properties was used as a potential host for supporting palladium nanoparticles. The structure and composition of the target nanocomposite, SBA-R/Im-NH2·Pd, were supported by infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), transmission electron microscopy (TEM), elemental analysis (CHNS), energy dispersive X-ray (EDX) and Brunauer-Emmett-Teller (BET) measurements. The efficiency of this porous inorganic-organic hybrid nanocomposite as a powerful catalyst in one of the most important carbon-carbon bond-forming process, the Heck coupling reaction of aryl halides with olefins, in aqueous media was also examined. This method has the advantages of high yields, cleaner reactions, simple methodology, short reaction times, easy workup, and greener conditions. In addition, the nanocatalyst can be easily separated from the reaction mixture and reused several times without significant decrease in activity and promises economic as well as environmental benefits.
- Jafari Nasab, Mina,Kiasat, Ali Reza
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p. 81614 - 81621
(2016/09/09)
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- A water-soluble palladium-salen catalyst modified by pyridinium salt showing higher reactivity and recoverability for Heck coupling reaction
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A novel and water-soluble palladium-salen catalyst modified by pyridinium salt was synthesized and characterized by NMR, HRMS, FT-IR, ICP, elemental analysis and UV-vis spectroscopy. The catalyst can efficiently catalyze the Heck reaction between aryl halides and olefins. The reaction using 0.5 mol% catalyst can achieve 98.3% conversion with 99% selectivity. The catalytic activity of catalyst modified by pyridinium salt is higher than that of un-modified one. Furthermore, the catalyst can be easily separated from reaction system by water wash and subsequently recycled for six runs without significant loss of activity and selectivity.
- Yuan, Linghua,Xu, Yun,Hu, Xingbang,Yang, Guoqiang,Wu, Youting
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- A water-soluble palladium-salen catalyst modified by pyridinium salt showing higher reactivity and recoverability for Heck coupling reaction
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A novel and water-soluble palladium-salen catalyst modified by pyridinium salt was synthesized and characterized by NMR, HRMS, FT-IR, ICP, elemental analysis and UVvis spectroscopy. The catalyst can efficiently catalyze the Heck reaction between aryl halides and olefins. The reaction using 0.5 mol% cat-alyst can achieve 98.3% conversion with 99% selectivity. The catalytic activity of catalyst modified bypyridinium salt is higher than that of un-modified one. Furthermore, the catalyst can be easily separatedfrom reaction system by water wash and subsequently recycled for six runs without significant loss ofactivity and selectivity.
- Yuan, Linghua,Xu, Yun,Hu, Xingbang,Yang, Guoqiang,Wu, Youting
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- Carboncarbon bond forming reactions: Application of covalently anchored 2,4,6-triallyloxy-1,3,5-triazine (TAT) Pd(II) complex over modified surface of SBA-15 to Heck, Suzuki, Sonogashira and Hiyama cross coupling reactions
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A highly active SBA-15-TAT-Pd(II) catalyst was synthesized from organofunctionalized SBA-15 and 2,4,6-triallyloxy-1,3,5-triazine. The catalyst was employed in carrying out Heck, "copper-free" Sonogashira, Suzuki and Hiyama cross coupling reactions. Under the optimized conditions the catalyst displays excellent catalytic activity in delivering the desired products in good to excellent yields. The catalytic system exhibited superior activity regarding the time taken for the completion of reaction, isolation, Pd loading (0.62 mmol%) and yields of products as compared to the earlier reported heterogeneous SBA-15 anchored Pd catalysts. The catalyst could be recycled and reused for five times without any appreciable loss of catalytic activity.
- Singh, Chandani,Jawade, Kiran,Sharma, Priti,Singh, Anand P.,Kumar, Pradeep
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- Acetamidine-palladium complex immobilized on γ-Fe2O3 nanoparticles: A novel magnetically separable catalyst for Heck and Suzuki coupling reactions
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A new palladium-Schiff base complex immobilized on iron oxide nanoparticles (γ-Fe2O3-acetamidine-Pd) was synthesized via the reaction of amino-functionalized γ-Fe2O3 with acetamide followed by the reaction with palladium acetate. Characterization of γ-Fe2O3-acetamidine-Pd was carried out by various techniques such as XRD, SEM, HRTEM, FT-IR, TGA, ICP, XPS and elemental analysis. γ-Fe2O3-acetamidine-Pd was successfully applied as a magnetically recyclable catalyst in Heck and Suzuki coupling reactions. By these protocols, aryl halides were coupled with olefins (Heck coupling reaction) and phenylboronic acid (Suzuki coupling reaction) to afford the corresponding products in moderate to high yields. Furthermore, the synthesized catalyst was separated easily by using an external magnet and recycled for five runs without appreciable loss of its catalytic activity. This journal is
- Sobhani, Sara,Ghasemzadeh, Maryam Sadat,Honarmand, Moones,Zarifi, Farzaneh
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p. 44166 - 44175
(2014/12/10)
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- Preoxidated polyacrylonitrile fiber mats supported copper catalyst for Mizoroki-Heck cross-coupling reactions
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Porous preoxidated polyacrylonitrile (PAN) fiber mats, which was prepared by electrospinning and then followed by thermal treatment, has been used for the immobilization of copper catalyst. FT-IR/ATR spectra and XRD pattern show that the linear polymer structure of the PAN fiber mat can be converted into the ladder molecular structure at the high temperature. The morphology of the copper catalyst supported on the preoxidated PAN fiber mats was examined by scanning electron microscopy (SEM). The catalytic activity and stability of the fiber mat supported copper catalyst have been evaluated using the Mizoroki-Heck cross-coupling reaction of aryl iodides with different acrylates. It was found that the catalytic activities of fiber mat supported copper catalyst could be significantly promoted by addition of small amount of additives, such as ethylene glycol.
- Shao, Linjun,Qi, Chenze
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- Iron-catalyzed cross-coupling reaction: Recyclable heterogeneous iron catalyst for selective olefination of aryl iodides in poly(ethylene glycol) medium
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An environmentally friendly iron-based catalyst supported on acac-functionalized silica was successfully prepared and evaluated as a heterogeneous catalyst for Mizoroki-Heck reaction of aryl iodides and olefins. Our catalytic system showed good activities that were comparable to that of palladium catalysts. The catalyst was simply recovered from the reaction mixture and recycled five times. Furthermore, the reaction was carried out in poly(ethylene glycol) as a green solvent. Interestingly, using this catalyst, aryl iodides were selectively olefinated in the presence of aryl bromides.
- Hajipour, Abdol Reza,Azizi, Ghobad
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p. 1030 - 1034
(2013/07/26)
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- Pd(diimine)Cl2 embedded heterometallic compounds with porous structures as efficient heterogeneous catalysts
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Four porous heterometallic coordination polymers were synthesized via a metalloligand strategy. All of them contain the [Pd(diimine)Cl2] moiety, which has good catalytic activity, and present remarkable versatility for catalysing Suzuki-Miyaura
- Huang, Sheng-Li,Jia, Ai-Quan,Jin, Guo-Xin
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p. 2403 - 2405
(2013/04/10)
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- A robust first-pass protocol for the heck-mizoroki reaction
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The Heck-Mizoroki (HM) reaction is one of the most widely used C-C bond-forming methods of contemporary synthesis. Notwithstanding this, these reactions frequently require significant optimization before efficient transformations can be obtained. We describe here the results of a study that aimed to establish a generic experimental protocol for HM reactions which enables acceptable yields from first-pass experiments. The methodology utilizes readily available stable catalysts and can be applied to a broad range of coupling partners.
- Murray, Paul M.,Bower, John F,Cox, David K,Galbraith, Ewan K,Parker, Jeremy S,Sweeney, Joseph B.
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p. 397 - 405
(2013/04/24)
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- Ni ion-containing immobilized ionic liquid on magnetic Fe3O 4 nanoparticles: An effective catalyst for the Heck reaction
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In this work, we synthesized Ni2+-containing 1-methyl-3-(3-trimethoxysilylpropyl) imidazolium chloride ionic liquid on magnetic Fe3O4 nanoparticles. The catalytic activity of these novel nanocomposites was finally evaluate
- Safari, Javad,Zarnegar, Zohre
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p. 821 - 828
(2013/09/02)
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- The ligand and base-free Pd-catalyzed oxidative Heck reaction of arylboronic acids and olefins
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Highly effective Pd-catalyzed Heck-type oxidative couplings between arylboronic acids and terminal olefins were reported. It is noteworthy that such reactions could be carried out in the absence of the base and the ligand.
- Sun, Peng,Zhu, Yan,Yang, Hailong,Yan, Hong,Lu, Linhua,Zhang, Xiang,Mao, Jincheng
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scheme or table
p. 4512 - 4515
(2012/07/14)
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- Highly effective recyclable palladium-catalyzed ligand-free heck reactions under aerobic conditions
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An effective protocol was developed for the Heck coupling reactions between various aryl halides and olefins. In the presence of 2 mol% of Pd(OAc) 2, the desired products could be obtained in good yields under ligand-free and aerobic conditions. The catalytic system could be easily recycled for five times with high efficiency. Georg Thieme Verlag Stuttgart. New York.
- Sun, Peng,Qu, Xiaoming,Li, Tingyi,Zhu, Yan,Yang, Hailong,Xing, Zeyong,Mao, Jincheng
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supporting information; experimental part
p. 150 - 154
(2012/02/04)
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- Ligand-free reusable palladium-catalyzed heck-type coupling reactions of hypervalent iodine reagents under mild conditions
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Highly effective palladium-catalyzed Heck-type couplings of hypervalent iodine reagents are reported for the first time. It is noteworthy that such reactions could be carried out in the absence of ligand at 40 °C and the catalytic system could be easily reused for five times. Copyright
- Qu, Xiaoming,Sun, Peng,Li, Tingyi,Mao, Jincheng
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supporting information; experimental part
p. 1061 - 1066
(2011/07/09)
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- Rhodium-catalysed alkoxycarbonylative cyclisation reactions of 1,6-enynes
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The rhodium-catalysed carbonylation of 1,6-enynes possessing an electron-deficient alkenyl moiety in an alcohol reagent in the presence of a rhodium complex proceeded stereo- and chemoselectively to afford exocyclic α,β-enoates.
- Ziyanak, Firat,Kus, Melih,Artok, Levent
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experimental part
p. 897 - 902
(2011/06/22)
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- Metallic samarium promoted self-coupling of baylis-hillman adducts to functionalized 1,5-hexadienes in the presence of the I2/ClCO 2Et/BiCl3 System
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A facile strategy for the self-coupling of Baylis-Hillman adducts to functionalized 1,5-hexadienes has been described. Promoted by the Sm/I 2/ClCO2Et/BiCl3 system, the present method allows for the conversion of MBH adducts to their corresponding 1,5-hexadienes.
- Bian, Haishan,Li, Jian,Li, Chunju,Wang, Gan,Duan, Zheng,Jia, Xueshun
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supporting information; experimental part
p. 1412 - 1414
(2010/08/22)
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- Heck reaction catalyzed by a recyclable palladium supported on shell powder
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Anovel palladium catalyst supported on shell powder has been prepared, and its application to the Heck reaction of aryliodides with olefins has been reported. The results showed that the novel catalyst had extremely high activities for the reactions with the average yield over 90%. Also, this catalyst showed excellent stability in Heck reactions, being reused three times. The catalyst was characterized by X-ray powder diffraction and field-emission scanned electron microscopy images, and the energy dispersive X-ray analyzer. Copyright
- Shen, Yong-Miao,Du, Yi-Jun,Zeng, Min-Feng,Zhi, Duo,Zhao, Sheng-Xian,Rong, Lin-Mei,Lv, Shao-Qin,Du, Lin,Qi, Chen-Ze
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experimental part
p. 631 - 635
(2010/11/04)
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- CATALYTIC WITTIG AND MITSUNOBU REACTIONS
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A catalytic Wittig method utilizing a phosphine including the steps of providing a phosphine oxide precatalyst and reducing the phosphine oxide precatalyst to produce the phosphine; forming a phosphonium ylide precursor from the phosphine and a reactant; generating a phosphonium ylide from the phosphonium ylide precursor; reacting the phosphonium yiide precursor with the aldehyde, ketone, or ester to form the olefin and the phosphine oxide which then reenters the cycle. The invention is also directed to a Mitsunobu reaction catalytic in phosphine.
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Page/Page column 15
(2010/11/03)
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- Synthesis and characterization of dithia[3.3](2,6)pyridinophane-containing polymers: Application to the palladium-catalyzed Heck reaction
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We synthesized zigzag polymers consisting of dithia[3.3](2,6)pyridinophane units that were flipped rapidly as a result of syn-[anti]-syn isomerization. Pyridinophane units were fixed in the syn form by complexation with palladium, and the resulting polyme
- Morisaki, Yasuhiro,Ishida, Tamao,Chujo, Yoshiki
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p. 1029 - 1032
(2007/10/03)
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- Reductive dehydroxylation of Baylis-Hillman adducts with low-valent titanium reagent: Syntheses of stereoselective trisubstituted alkenes
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The Baylis-Hillman adducts prepared from aromatic aldehydes and methyl acrylate underwent smooth dehydroxylation with concomitant olefin isomerisation with low-valent titanium reagent to provide the trisubstituted alkenes with high (E)-selectivity.
- Shadakshari, Uma,Nayak, Sandip K.
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p. 4599 - 4602
(2007/10/03)
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- A facile one-pot synthesis of methyl(2E)-2-methylalk-2-enoates from Baylis-Hillman adducts under microwave irradiation
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A facile procedure for the synthesis of the title compound is described.
- Ravichandran
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p. 2055 - 2057
(2007/10/03)
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- P(RNCH2CH2)3N: An efficient promoter for the direct synthesis of E-α,β-unsaturated esters
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Upon reacting ethyl acetate or methyl propionate with a variety of aromatic aldehydes in the presence of 1.06-1.2 equiv. of the pro-azaphosphatranes, P(MeNCH2CH2)3N, P(i-PrNCH2CH2)3N or [P(i-PrNCH2CH2)2(NHCH2CH 2)N at 40-50°C for 2-6 h in isobutyronitrile, the corresponding α,β-unsaturated esters were formed as the only products. Ethyl acetate reacts with aldehydes to form exclusively E-isomers while the higher homologue methyl propionate gives rise to a mixture of E and Z isomers with the former as the major product. When used as the solvent, methyl propionate selectively forms the E-α,β-unsaturated ester. The reaction is not as successful for the preparation of α,β-unsaturated ketones.
- Kisanga, Philip,D'sa, Bosco,Verkade, John
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p. 8047 - 8052
(2007/10/03)
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- Palladium catalysed regio and stereoselective reduction of Baylis- Hillman coupling products derived allylic acetates
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Acetates derived from a variety of the Baylis-Hillman products undergo reduction with HCOOH in the presence of Et3N, Pd(OAc)2, and dppe (or tri- isopropylphosphite) to yield the corresponding trisubstituted Z-olefins in good yields d
- Pachamuthu, Kandaswamy,Vankar, Yashwant D.
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p. 5439 - 5442
(2007/10/03)
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- Reductive Carbonylation of gem-Dihalogenocyclopropanes by Pentacarbonyliron(0) in the Presence of Sodium Methoxide
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The reaction of gem-dihalogenocyclopropanes derivatives with (tetracarbonyl)(methoxycarbonylato)ferrate(I-) has been investigated; gem-dibromocyclopropanes and gem-chlorobromocyclopropane derivatives are reduced and carbonylated.It could be shown that a bromo ester such as methyl 1-bromo-2-phenylcyclopropanecarboxylate is an intermediate in the transformation of 1,1-dibromo-2-phenylcyclopropane into methyl cis- and trans-2-phenylcyclopropanecarboxylates and dimethyl 2-phenyl-1,1-cyclopropanedicarboxylate.
- Reyne, Francoise,Waegell, Bernard,Brun, Pierre
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p. 1162 - 1167
(2007/10/02)
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- Isoxazolidine compounds, XI: 2,2-dialkyl-3-aryl-5-oxoisoxazolidinium salts: Cyclic analogues of Polonovski intermediates
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The 2-methyl-3-aryl-5-oxoisoxazolidines 1 are quaternized with 'magic methyl' or triethyloxonium tetrafluoroborate, respectively. The very sensitive cations 2 and 3, respectively, undergo easily solvolysis in methanol without recognizable Polonovski rearrangement.
- Steudle,Stamm
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p. 329 - 331
(2007/10/02)
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- Carbonyl olefination with α-stannyl ester enolates: a new synthesis of α,β-unsaturated esters
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The reaction of α-stannyl ester enolates with carbonyl compounds is described. α,β-Unsaturated esters are obtained in good yields.A reaction mechanism is proposed.
- Zapata, Antonio,Nunez, Beatriz M.,Ferrer, Fernando J.
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- From Stoichiometry to Catalysis: Electroreductive Coupling of Alkynes and Carbon Dioxide with Nickel-Bipyridine Complexes. Magnesium Ions as the Key for Catalysis
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The incorporation of carbon dioxide into nonactivated alkynes catalyzed by electrogenerated nickel-bipyridine complexes affords α,β-unsaturated acids in moderate to good yields.The electrocarboxylation reaction was undertaken on a preparative scale in the presence of a sacrificial magnesium anode: the formation of acids from alkynes is stoichiometric with respect to the nickel complex if performed in a two-compartment cell but can be made catalytic in a single-compartment cell.An intermediate nickelacycle was isolated from the reaction with 4-octyne.The cleavage ofthis metallacycle by magnesium ions is the key step to explain catalysis.
- Derien, Sylvie,Dunach, Elisabet,Perichon, Jacques
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p. 8447 - 8454
(2007/10/02)
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- A facile conversion of (Z)-2-alkenoic esters into the (E)-isomers with diphenyl disulfide
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Diphenyl disulfide is shown to be an efficient catalyst for the isomerization of (Z)-2-alkenoic esters to (E)-2-alkenoic esters in boiling tetrahydrofuran.
- Miyata,Shinada,Ninomiya,Naito
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p. 1123 - 1125
(2007/10/02)
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- A STEREOSELECTIVE SYNTHESIS OF (Z)-α,β-DISUBSTITUTED ACRYLATES
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A new route for (Z)-α,β-disubstituted acrylate is described which is made up of 1) stereoselective reduction of ketones 3 and 2) conversion of the resulting syn-2 into (Z)-1.
- Shimagaki, Masayuki,Shiokawa, Manabu,Sugai, Kazunori,Teranaka, Tomoko,Nakata, Tadashi,Oishi, Takeshi
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p. 659 - 662
(2007/10/02)
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- C=C Double Bond Insertion in Catalytic C-H Activation. Dehydrogenative Cross Coupling of Arenes with Olefins
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The reaction of benzene with methyl acrylate and ethylene catalyzed by RhCl(CO)(PMe3)2 under irradiation gave methyl cinnamate and styrene, respectively.The reaction of toluene afforded meta-substituted isomers as major products.
- Sasaki, Koushi,Sakakura, Toshiyasu,Tokunaga, Yuko,Wada, Keisuke,Tanaka, Masato
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p. 685 - 688
(2007/10/02)
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- Lewis Acid Catalysis of Photochemical Reactions. 7. Photodimerization and Cross-Cycloaddition of Cinnamic Esters
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The effects of Lewis acid complexation upon the molecular structure, solid-state photodimerization, and solution dimerization and cross-cycloaddition of cinnamic esters have been investigated.Comparison of crystal structures for free and SnCl4-complexed ethyl cinnamate indicates that the enone double bonds are lengthened, the single bonds are shortened, and the enone conformation changes from s-cis to s-trans upon complexation.These changes are consistent with calculated changes in ? bonding and net charges.Solid-state photodimerization of free and complexed cinnamic esters and related molecules yield syn head-to-tail (α-truxillate) dimers.In most cases the Lewis acid complexes dimerize more efficiently and stereoselectively than the free esters.Photodimerization and cross-cycloaddition of methyl cinnamate in dilute solution is also catalyzed by Lewis acids.The mechanism of these reactions involves electronic excitation of a ground-state methyl cinnamate-Lewis acid complex followed by reaction of the excited complex with ground-state ester (dimerization) or simple olefin (cross-cycloaddition).The catalytic effect of Lewis acids is attributed to an increase in excited-state lifetime and reactivity.
- Lewis, Frederick D.,Quillen, Suzanne L.,Hale, Paul D.,Oxman, Joe D
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p. 1261 - 1267
(2007/10/02)
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- Lewis Acid Catalysis of Photochemical Reactions. 4. Selective Isomerization of Cinnamic Esters
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The spectroscopic properties and photoisomerization reactions of several (E)- and (Z)-cinnamic esters, bis cinnamic esters, and model esters and lactones in the presence and absence of Lewis acids have been investigated.The use of Lewis acids such as BF3
- Lewis, Frederick D.,Oxman, Joe D.,Gibson, Lester L.,Hampsch, Hilary L.,Quillen, Suzanne L.
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p. 3005 - 3015
(2007/10/02)
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- ETUDE DE LA REACTION CHLOROCARBENE-ACETALS DE CETENES. I. SYNTHESE D'ESTERS α,β-ETHYLENIQUES.
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The reaction of chloro, chloromethyl and chlorophenyl carbenoids with ketene alkylsilylacetals has been studied.Excellent yields of cyclopropanation were observed and the unstable chlorocyclopropanone acetals formed were thermally rearranged in high yield into α-substituted α,β-ethylenic esters.This new method for the synthesis of unsaturated esters appeared complementary of the known-ones.
- Slougui, N.,Rousseau, G.
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p. 2643 - 2652
(2007/10/02)
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- SYNTHESE STEREOSELECTIVE D'ESTERS α,β-ETHYLENIQUES α-METHYLES Z OU E PAR LA REACTION DE WITTIG-HORNER A PARTIR DE PHOSPHONATES OU D'OXYDES DE PHOSPHINE
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The reaction of α-branched aldehydes with diethyl 1-carbomethoxyethyl phosphonate 1b in THF/nBuLi at low temperature leads stereoselectively to Z α-methyl α,β-unsaturated esters.From a linear aldehyde, the reaction is less stereoselective, while from α,β-unsaturated ones, the E isomers are predominantly formed in good yields.From diphenyl 1-carbomethoxyethyl phosphine oxide 2b, E α-methyl α,β-unsaturated esters are stereoselectively formed either in DMF/tBuOK or in phase transfer conditions, whatever the starting aldehyde is, also in good yields.This reagent can thus advantageously replace the corresponding P-ylid.In all cases, the reaction conditions are determined so that by-products formation is minimized.
- Etemad-Moghadam, Guita,Seyden-Penne, Jacqueline
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p. 5153 - 5166
(2007/10/02)
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